Correspondence, diplomas, certificates of membership, and invitations to special meetings or to ceremonies honoring Leidy as a scientist, are grouped here. Besides his earned diplomas from school and University, certificates of honorary membership in local organizations, in national groups and in European societies are included. Since our list of 75 does not mention every organization recorded in a published list of such honoring institutions, the College of physicians of Philadelphia was asked to check for additional certificates. Dr. McDaniel reported that “no cataloged Leidy diplomas or certificates” are in its library.